PDGFRA and gastrointestinal stromal tumor: Higher percentage of nonstomach GIST patients had c-KIT exon 9 mutations (nonstomach vs stomach, 94.4% vs 5.6%) and wild-type c-KIT/PDGFRA (nonstomach vs stomach, 76.5% vs 23.5%) than stomach GIST patients (P = 0.01).